function s1_generate_a_series_of_files() {
         for i in {1..100};do echo $i>/tmp/new_file$i; done
}

function s2_list_4_files_in_long_format_about_account_and_group() {
         ls -l /etc/passwd /etc/shadow /etc/group /etc/gshadow|sort -d
}

function s3_find_items_related_to_given_username() {
        grep -h $1 /etc/passwd /etc/shadow|sort -d
}

function s4_find_items_related_to_given_group_name() {
        grep -h $1 /etc/group /etc/gshadow|sort -d 
}

function s5_create_groups_for_given_group_names() {
        groupadd rnd&&groupadd itoperation
}

function s6_create_users_and_set_their_group_as_required() {
        useradd -G rnd adam && useradd -G rnd bob && useradd -G itoperation calvin && useradd -G itoperation david && useradd -G rnd edward
}

function s7_change_users_shell() {
        usermod -s /usr/bin/sh adam && usermod -s /usr/bin/sh edward
}

function s8_set_password_change_policy() {
        passwd -n 10 -x 60 -w 10 adam && passwd -n 10 -x 60 -w 10 bob && passwd -n 10 -x 60 -w 10 david && passwd -n 10 -x 60 -w 10 calvin && passwd -n 10 -x 60 -w 10 edward
}

function s9_set_password_for_five_users() {
    usernames=(adam bob calvin david edward)
        for i in $(seq 1 5);do echo ${!i};echo $(( $i-1 ));done
            echo "${usernames[0]}:$1" | chpasswd
                echo "${usernames[1]}:$2" | chpasswd
                echo "${usernames[2]}:$3" | chpasswd
                echo "${usernames[3]}:$4" | chpasswd
                echo "${usernames[$(( $i-1 ))]}:$5" | chpasswd
}

function s10_lock_bobs_password() {
        usermod -L bob 
}
function s11_include_adam_into_wheel_group() {
        usermod -a -G wheel adam
}
function s12_change_files_permission() {
        for i in {1..33};do chmod -R 640 /tmp/new_file$[3*i]; done
}

#s1_generate_a_series_of_files
#s2_list_4_files_in_long_format_about_account_and_group
#s3_find_items_related_to_given_username
#s12_change_files_permission
#s11_include_adam_into_wheel_group
#s10_lock_bobs_password
#s8_set_password_change_policy
#s8_set_password_change_policy
